Figure 1
From: Ultra-stable clock laser system development towards space applications
Fractional Allan deviation (linear drift removed) of a beat note against stationary system.
Blue circles indicate a full 24 h measurement with a minimum instability of 2.5 × 10−15 in 1 s. The best 1 hour slot within the 24 hour measurement is plotted with green squares with a minimum of 7.9 × 10−16 in less than 1 s. The estimated thermal noise limit for the cavity is 5 × 10−16, as presented by red-dashed line.
